ii PATTERN OF CONVOLUTIONS. 139 



tigations directed to the determination of these 

 very questions, by skilled anatomists) which we 

 now possess, leads to the conviction that, so far 

 from the posterior lobe, the posterior cornu, and 

 the hippocampus minor, being structures peculiar 

 to and characteristic of man, as they have been 

 over and over again asserted to be, even after the 

 publication of the clearest demonstration of the 

 reverse, it is precisely these structures which are 

 the most marked cerebral characters common to 

 man with the apes. They are among the most dis- 

 tinctly Simian peculiarities which the human or- 

 ganism exhibits. 



As to the convolutions, the brains of the apes 

 exhibit every stage of progress, from the almost 

 smooth brain of the Marmoset, to the Orang and 

 the Chimpanzee, which fall but little below Man. 

 And it is most remarkable that, as soon as all 

 the principal sulci appear, the pattern according 

 to which they are arranged is identical with that 

 of the corresponding sulci of man. The surface of 

 the brain of a monkey exhibits a sort of skeleton 

 map of man's, and in the man-like apes the details 

 become more and more filled in, until it is only 

 in minor characters, such as the greater excavation 

 of the anterior lobes, the constant presence of fis- 

 sures usually absent in man, and the different dis- 

 position and proportions of some convolutions, that 

 the Chimpanzee's or the Orang's brain can be 

 structurally distinguished from Man's. 



